Fernando Alonso won a dramatic Malaysian GP yesterday, but while he and fellow podium finisher Lewis Hamilton were matter-of-fact about their performances, the star was the 22-year-old Mexican Sergio Perez, who drove the race of his life to bring his unfancied Sauber home a valiant second.

A downpour before the start created the drama that allowed Perez to challenge. Hamilton led his McLaren team-mate Jenson Button off the line and Lotus's Romain Grosjean spun himself into Michael Schumacher after bursting momentarily into third place. One team kept cool in the rain, Sauber astutely calling in Perez at the end of that eventful opening lap for full wet tyres instead of the intermediates on which everyone started. By the time the rest had followed suit – and the race had been suspended on lap nine for almost an hour as conditions worsened – Perez was up to third.

When it resumed behind the safety car, Hamilton led Button, Perez, Webber, Alonso and Vettel. Button's race fell apart after he collided with Narain Karthikeyan's HRT and damaged his front wing, Webber was swallowed up by the Ferrari of Alonso, and Hamilton fell back with a tyre change.

Perez's chances, however, were just opening up. From the 17th lap until the finish, it was Perez against Alonso, youngster against old stager.

Alonso was 7.7 seconds ahead on the 28th lap, which was half the distance. But Perez slashed that to just 1.3secs by lap 39. The atmosphere, so sodden earlier, was now electric as everyone willed him on.

Alonso dived for the pits on the 40th lap and took on medium slick tyres, Perez came a lap later and took the harder tyres, as Sauber crucially added more frontal downforce. By lap 42 the gap was 7.1secs again, and the fairytale seemed to be over, but nobody told Perez that. Lap by lap he ate into the Ferrari's advantage; by lap 49 he was only half a second behind and it seemed only a matter of time. But then he slid wide in Turn 14 leading on to the back straight, and this time the dream really was over. He managed to recover, and by the chequered flag on lap 56 the gap was down from 5.3secs to 2.2secs, but Alonso had made it.

The Spaniard was in impressive form but though he thoroughly deserved credit for grabbing the chance when he saw it, Perez was the man of the match after a truly wonderful race. And he happily savoured the greatest day of his life and the best performance by a Mexican since the great Pedro Rodriguez in Holland back in 1971, even if he was ruing a chance missed.

"I think it could have been my win," Perez said, "because I was catching Fernando and knew that I had to get him soon because in all the high-speed sectors my front tyres were losing performance. Then I ran wide, and touched a kerb which was completely wet.

"The team did an incredible job, and always called me in at the right time. Our pace was fantastic, really quick. I'm very happy for them."

Hamilton had an untroubled run to third, as Webber came through to fourth after Vettel had also hit the innocent Karthikeyan on the 48th lap and torn up his left rear tyre. The world champion eventually finished 11th and had choice words for the Indian backmarker. "To lose the race how I did is very frustrating," Vettel said. "Some people need to look more where they are going."

Alonso, world champion in 2005 and 2006, spoke with admirable understatement. "It was a big surprise today, the win. We were not competitive in Australia or here, but we scored 25 points. It's an unbelievable result, all about keeping calm in some extreme conditions when there was a lot of water initially. This is a Sunday we will remember."

But, he added, the result changed little even though it put him into the lead of the world championship from Hamilton and Button. "We are in a situation we don't want, fighting just to get into the final session in qualifying. They will be happy for the next few days in the factory, but that doesn't change the fact that we have to keep improving."

Hamilton was less downbeat post-race than in Melbourne a week ago, when he also failed to win despite starting on pole. "I think I have to be satisfied," he said. "Congratulations to Fernando and Sergio, they did a better job and were just very quick, equally as quick as me, if not quicker.

"In one of the stops I lost time with a problem with the front right, and I also had to look after the tyres. Of course I would have liked more points but I can't really complain. I feel very fortunate the way the track was today that I managed to finish, let alone be on the podium with good points."

If Hamilton, one of the six world champions on the grid this season, feels fortunate to be on such a rain-soaked podium, what is the true value of Perez's achievement? This will be remembered as a day when a young driver upstaged the stars and earned his spurs.